I was watching a Nova episode on batteries and they showed a new type of Lithium Metal battery that used a plastic material that separated the positive and negative halves. The unique thing about this new Lithium Metal battery was that it was not prone to the existing problems of Lithium Metal batteries and did not catch fire when punctured. They even started cutting portions of the battery off with a scissor and it continued powering an iPad.
Yup, same principle. The problem all solid state batteries share is that the solid electrolyte isn't a good conductor- plastic isn't great for that. Despite that it's the current favorite for reasons of cost. NB that the plastic is very very special.
